After two rain-interrupted defeats, Frenchman Jo Wilfried-Tsonga has thrown in the towel at the invitational Kooyong Classic in Melbourne, citing exhaustion and the need to rest ahead of the Australian Open.

The world number six, who complained of jet-lag after slumping to a straight-sets loss to Austria's Jurgen Melzer in the first round, was beaten by Japan's Kei Nishikori 1-6 6-4 6-1 and has elected not to play his third and final match, tournament director Colin Stubs said.

"He's a bit jet-lagged and he just felt like 'if I'm going to give myself half a chance I've got to have a day off.' It's not an injury per se," Stubs said.

Tsonga arrived in Melbourne this week after a long-haul flight from the Middle East where he won the Qatar Open following his appearance at an exhibition tournament in Abu Dhabi.

His withdrawal followed Canadian Milos Raonic's pull-out from the eight-man field at Kooyong Lawn Tennis Club on Wednesday after his first-round defeat to Mardy Fish.

Raonic, who won the Chennai Open on Sunday, withdrew citing a stomach bug.

Organisers were forced to scramble to find replacements to pad out the draw, with American Sam Querrey and Serbia's Viktor Troicki drafted in to play each other in an exhibition match on Friday.

"You live to fight another day," Stubs said of Tsonga's exit. "If I cracked it with everyone who did that to me, I wouldn't have an event."

American world number eight Mardy Fish will play Melzer for a place in Saturday's final against Australian teenager Bernard Tomic who ground down 15th-ranked Frenchman Gael Monfils in three sets on Thursday.

Andy Murray will also make an appearance at the warm-up tournament on Friday, playing a one-off exhibition match against Argentine veteran David Nalbandian as he seeks a last competitive hit-out before the year's first grand slam.

The Kooyong Classic guarantees players three matches on the same court surface used at Melbourne Park.